Fig. 3. Synthesis of ATP-γ-alkyne and labeling of DNA modifications.

a MS characterization of ATP-γ-alkyne synthesis. Left panel, the mass spectrum of ATP (C₁₀H₁₅N₅O₁₃P₃, [M + H]⁻: 505.98847, calculated; 505.98488, found); right panel, the mass spectrum of ATP-γ-alkyne (C₁₃H₁₈N₆O₁₂P₃, [M + H]⁻: 543.02010, calculated; 543.01591, found). b Melting curve analysis of the cleavage products of 5hmU-contained dsDNA after labeled by 5-HMUDK and ATP-γ-alkyne. c MS characterization of 5fU reduction. Left panel, the mass spectrum of 5fU (C₅H₄N₂O₃, [M + H]⁻: 140.02274, calculated; 140.01658, found); right panel, the mass spectrum of reduction product 5hmU (C₅H₅N₂O₃, [M + H]⁻: 141.03057, calculated; 141.03095, found).